function Fn() {
    this.name = 'Fn'
}

const f = new Fn();

console.log(f instanceof Fn)        // true
console.log(f instanceof Object)    // true

class Animal {
    constructor(name) {
        this.name = name
    }
}

const dog = new Animal('dog')
console.log(dog instanceof Animal)  // true
console.log(dog instanceof Object)  // true